This is an interactive problem.You are given a sorted in increasing order singly linked list. You should find the minimum integer in the list which is greater than or equal to x.More formally, there is a singly liked list built on an array of n elements. Element with index i contains two integers: valuei is the integer value in this element, and nexti that is the index of the next element of the singly linked list (or -1, if the current element is the last). The list is sorted, i.e. if nexti ≠  - 1, then valuenexti > valuei.You are given the number of elements in the list n, the index of the first element start, and the integer x.You can make up to 2000 queries of the following two types:  ? i (1 ≤ i ≤ n) — ask the values valuei and nexti,  ! ans — give the answer for the problem: the minimum integer, greater than or equal to x, or ! -1, if there are no such integers. Your program should terminate after this query. Write a program that solves this problem.

The first line contains three integers n, start, x (1 ≤ n ≤ 50000, 1 ≤ start ≤ n, 0 ≤ x ≤ 109) — the number of elements in the list, the index of the first element and the integer x.

To print the answer for the problem, print ! ans, where ans is the minimum integer in the list greater than or equal to x, or -1, if there is no such integer.

NoteYou can read more about singly linked list by the following link: https://en.wikipedia.org/wiki/Linked_list#Singly_linked_list The illustration for the first sample case. Start and finish elements are marked dark.

module main;
__gshared:
import core.bitop, std.algorithm, std.bigint, std.bitmanip, std.complex,
	std.container, std.conv, std.datetime, std.functional, std.math, std.meta;
import std.numeric : Fft, fft, gcd, inverseFft;
import std.parallelism, std.random, std.range, std.regex, std.stdio, std.string,
	std.traits, std.typecons, std.uni, std.variant;

alias pair(X, Y) = Tuple!(X, "fi", Y, "se");
alias mp = make_pair;
alias pii = pair!(int, int);
alias pll = pair!(long, long);
alias gcd = std.numeric.gcd;
alias lint = long;
alias rbt = RedBlackTree;
///modulo
enum mod = 10 ^^ 9 + 7, mod2 = mod + 2;
public
{
	pure nothrow
	{
		///lcm
		T lcm(T)(auto ref T a, auto ref T b)
		{
			return a / gcd(a, b) * b;
		}
		///make_pair
		pair!(X, Y) make_pair(X, Y)(in X x_, in Y y_)
		{
			return tuple!(X, "fi", Y, "se")(x_, y_);
		}
		///BigInt greatest common divizor
		BigInt gcd(BigInt a, BigInt b)
		{
			while (b)
			{
				a %= b;
				swap(a, b);
			}
			return a;
		}
		///square
		@property X sqr(X)(in X a_)
		{
			return a_ * a_;
		}
		///cube
		@property X cub(X)(in X a_)
		{
			return a_ * a_ * a_;
		}
		///integer size
		int sz(T)(T a) if (hasLength!T)
		{
			return cast(int) a.length;
		}
		///posicion lower bound
		size_t lowb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (!(a[m] < g))
					r = m;
				else
					l = m;
			}
			return (!(a[l] < g)) ? l : r;
		}
		///posicion upper bound
		size_t upb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (g < a[m])
					r = m;
				else
					l = m;
			}
			return (g < a[l]) ? l : r;
		}
		///posicion binary search
		size_t binf(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			auto pos = lowb(a, g);
			return (g == a[pos]) ? pos : a.length;
		}
		///binary search
		bool binary_search(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			return binf(a, g) != a.length;
		}
	}
	///write an array
	void putarr(X)(in X a, in char ch = ' ') if (isInputRange!X)
	{
		writefln("%(%s" ~ ch ~ "%)", a);
	}
	///write a matrix
	void putarr(X)(in X a)
			if (isInputRange!X && isInputRange!(ElementType!X) && !isSomeString!(ElementType!X))
	{
		writefln("%(%(%s %)\n%)", a);
	}
	///get an array
	bool getarr(X)(X a, in size_t n)
	{
		bool b = 1;
		foreach (ref i; a[0 .. n])
			b = input(&i);
		return b;
	}
	///read without format
	bool input(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		return s == ptrs.length;
	}
	///readln without format
	bool read(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		readln;
		return s == ptrs.length;
	}
	///opening file
	nothrow auto inf(in char* name)
	{
		return freopen(name, "r", core.stdc.stdio.stdin);
	}
	///closing file
	nothrow auto ouf(in char* name)
	{
		return freopen(name, "w", core.stdc.stdio.stdout);
	}
	///parsing array from line
	@property auto arread(T)()
	{
		return readln.splitter.map!(to!(T)).array;
	}
	///outbuffer
	void enter(T...)(T args)
	{
		writeln(args);
		stdout.flush;
	}
}
//foreach_reverse isAlpha isNumber isWhite isLower isUpper toLower toUpper mixin
//cumulativeFold return static heapify join filter foreach
//------------------------------------------program beginning--------------------------

void main()
{
	version (home)
	{
		// freopen("input.txt", "r", core.stdc.stdio.stdin);
		//freopen("output.txt", "w", core.stdc.stdio.stdout);
		/*StopWatch sw;
		sw.start;
		scope (exit)
		{
			sw.stop;
			stderr.writefln("\nTime: %d ms", sw.peek.msecs);
		}*/
	}
	// int n;
	// loop: while (read(n))
	// {

	// }
	auto gen = Random(unpredictableSeed);
	/*foreach (i; 0 .. 4)
	{
		writeln(uniform(1, 6, gen));
	}*/
	int n, st, x;
	read(n, st, x);
	writeln("? ", st);
	Tuple!(int, int, int)[] d;
	stdout.flush;
	int val, nx;
	read(val, nx);
	d ~= tuple(val, st, nx);

	foreach (_; 0 .. min(n - 1, 999))
	{
		int id = uniform(1, n + 1, gen);
		writeln("? ", id);
		stdout.flush;
		read(val, nx);
		if (val == -1)
			assert(0);
		d ~= tuple(val, st, nx);
	}
	auto f = sort(d);
	auto pos = cast(int)(f.lowerBound(tuple(x, 0, 0)).length) - 1;
	if (pos < 0)
	{
		writeln("! ", d[0][0]);
		stdout.flush;
		return;
	}
	auto h = d[pos];
	while (h[0] < x)
	{
		if (h[2] == -1)
		{
			writeln("! ", -1);
			stdout.flush;
			return;
		}
		writeln("? ", h[2]);
		stdout.flush;
		h[1] = h[2];
		read(h[0], h[2]);
		if (h[0] == -1)
			assert(0);
	}
	writeln("! ", h[0]);
	stdout.flush;
}

/+ dub.sdl:
    name "B"
    dependency "dcomp" version=">=0.6.0"
+/

import std.stdio, std.algorithm, std.range, std.conv;
// import dcomp.foundation, dcomp.scanner;

int main() {
    auto sc = new Scanner(stdin);
    int n, s, x;
    sc.read(n, s, x); s--;
    int[] v = new int[n];
    int[] nx = new int[n];
    void query(int p) {
        writeln("? ", p+1);
        stdout.flush;
        sc.read(v[p], nx[p]);
        if (nx[p] != -1) nx[p]--;
    }
    void ans(int x) {
        writeln("! ", x);
        stdout.flush;
    }
    import std.random;
    auto gen = Random(unpredictableSeed);
    query(s);
    if (x <= v[s]) {
        ans(v[s]);
        return 0;
    }
    int ma = v[s], mp = s;
    foreach (ph; 0..999) {
        int p = uniform(0, n);
        query(p);
        if (ma < v[p] && v[p] < x) {
            ma = v[p];
            mp = p;
        }
    }
    while (mp != -1) {
        query(mp);
        if (x <= v[mp]) {
            ans(v[mp]);
            return 0;
        }
        mp = nx[mp];
    }
    ans(-1);
    return 0;
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/foundation.d */
// module dcomp.foundation;

static if (__VERSION__ <= 2070) {
    template fold(fun...) if (fun.length >= 1) {
        auto fold(R, S...)(R r, S seed) {
            import std.algorithm : reduce;
            static if (S.length < 2) {
                return reduce!fun(seed, r);
            } else {
                import std.typecons : tuple;
                return reduce!fun(tuple(seed), r);
            }
        }
    }

}
version (X86) static if (__VERSION__ < 2071) {
    import core.bitop : bsf, bsr, popcnt;
    int bsf(ulong v) {
        foreach (i; 0..64) {
            if (v & (1UL << i)) return i;
        }
        return -1;
    }
    int bsr(ulong v) {
        foreach_reverse (i; 0..64) {
            if (v & (1UL << i)) return i;
        }
        return -1;
    }
    int popcnt(ulong v) {
        int c = 0;
        foreach (i; 0..64) {
            if (v & (1UL << i)) c++;
        }
        return c;
    }
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/scanner.d */
// module dcomp.scanner;

class Scanner {
    import std.stdio : File;
    import std.conv : to;
    import std.range : front, popFront, array, ElementType;
    import std.array : split;
    import std.traits : isSomeChar, isStaticArray, isArray;
    import std.algorithm : map;
    File f;
    this(File f) {
        this.f = f;
    }
    char[512] lineBuf;
    char[] line;
    private bool succ() {
        import std.range.primitives : empty, front, popFront;
        import std.ascii : isWhite;
        while (true) {
            while (!line.empty && line.front.isWhite) {
                line.popFront;
            }
            if (!line.empty) break;
            if (f.eof) return false;
            line = lineBuf[];
            f.readln(line);
        }
        return true;
    }

    private bool readSingle(T)(ref T x) {
        import std.algorithm : findSplitBefore;
        import std.string : strip;
        import std.conv : parse;
        if (!succ()) return false;
        static if (isArray!T) {
            alias E = ElementType!T;
            static if (isSomeChar!E) {

                auto r = line.findSplitBefore(" ");
                x = r[0].strip.dup;
                line = r[1];
            } else {
                auto buf = line.split.map!(to!E).array;
                static if (isStaticArray!T) {

                    assert(buf.length == T.length);
                }
                x = buf;
                line.length = 0;
            }
        } else {
            x = line.parse!T;
        }
        return true;
    }
    int read(T, Args...)(ref T x, auto ref Args args) {
        if (!readSingle(x)) return 0;
        static if (args.length == 0) {
            return 1;
        } else {
            return 1 + read(args);
        }
    }
}

module solution;
import std.algorithm;
import std.array;
import std.random;
import std.range;
import std.stdio;
import std.typecons;

immutable int half = 999;
immutable int NA = -1;

void main ()
{
//	rndGen.seed (12526362);
	int n, start, x;
	readf (" %s %s %s", &n, &start, &x);
	alias Node = Tuple !(int, q{value}, int, q{next});
	auto a = new Node [n + 1];
	a[] = Node (NA, NA);
	auto p = n.iota.array;
	randomShuffle (p);
	p[] += 1;
	p = p.take (min (half, n)).array;

	void ask (int c)
	{
		if (a[c].value != NA)
		{
			return;
		}
		writeln ("? ", c);
		stdout.flush ();
		readf (" %s %s", &a[c].value, &a[c].next);
	}

	void answer (int v)
	{
		writeln ("! ", v);
		stdout.flush ();
	}

	ask (start);
	int closest = start;
	foreach (c; p)
	{
		ask (c);
		if (a[c].value < x)
		{
			if (a[closest].value < a[c].value)
			{
				closest = c;
			}
		}
	}

	foreach (i; 0..half)
	{
		ask (closest);
		if (a[closest].value >= x)
		{
			answer (a[closest].value);
			return;
		}
		if (a[closest].next == NA)
		{
			answer (NA);
			return;
		}
		closest = a[closest].next;
	}

	assert (false);
}

import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }

uint xrand() {
  static uint x = 314159265, y = 358979323, z = 846264338, w = 327950288;
  uint t = x ^ x << 11; x = y; y = z; z = w; return w = w ^ w >> 19 ^ t ^ t >> 8;
}

// floor(sqrt(a))
long floorSqrt(long a) {
  import core.bitop : bsr;
  import std.algorithm : min;
  long b = a, x = 0, y = 0;
  for (int e = bsr(a) & ~1; e >= 0; e -= 2) {
    x <<= 1;
    y <<= 1;
    if (b >= (y | 1) << e) {
      b -= (y | 1) << e;
      x |= 1;
      y += 2;
    }
  }
  return x;
}

int N, S, X;
debug {
  int[] V, E;
}

alias List = Tuple!(int, "value", int, "next");
List Ask(int i) {
  List ret;
  debug {
    ret.value = V[i];
    ret.next = E[i];
  } else {
    writeln("? ", i + 1);
    stdout.flush;
    ret.value = readInt();
    ret.next = readInt() - 1;
  }
  debug {
    writeln("Ask ", i, " = ", ret);
  }
  return ret;
}

void Answer(int v) {
  writeln("! ", v);
  stdout.flush;
  import core.stdc.stdlib;
  exit(0);
}

void main() {
  N = readInt();
  S = readInt() - 1;
  X = readInt();
  debug {
    V = new int[N];
    E = new int[N];
    foreach (i; 0 .. N) {
      V[i] = readInt();
      E[i] = readInt() - 1;
    }
  }

  auto list = new List[N];
  list[] = List(-58, -58);

  list[S] = Ask(S);
  if (list[S].value >= X) {
    Answer(list[S].value);
  }

  int[] perm = iota(N).array;
  foreach (j; 0 .. N) {
    swap(perm[xrand() % (j + 1)], perm[j]);
  }

  int im = S;
  const m = cast(int)(floorSqrt(N));
  foreach (j; 0 .. m) {
    const i = perm[j];
    list[i] = Ask(i);
    if (list[i].value < X) {
      if (list[im].value < list[i].value) {
        im = i;
      }
    }
  }

  for (int i = im; ; ) {
    i = list[i].next;
    if (i < 0) {
      Answer(-1);
    }
    list[i] = Ask(i);
    if (list[i].value >= X) {
      Answer(list[i].value);
    }
  }
}

module main;
__gshared:
import core.bitop, std.algorithm, std.bigint, std.bitmanip, std.complex,
	std.container, std.conv, std.datetime, std.functional, std.math, std.meta;
import std.numeric : Fft, fft, gcd, inverseFft;
import std.parallelism, std.random, std.range, std.regex, std.stdio, std.string,
	std.traits, std.typecons, std.uni, std.variant;

alias pair(X, Y) = Tuple!(X, "fi", Y, "se");
alias mp = make_pair;
alias pii = pair!(int, int);
alias pll = pair!(long, long);
alias gcd = std.numeric.gcd;
alias lint = long;
alias rbt = RedBlackTree;
///modulo
enum mod = 10 ^^ 9 + 7, mod2 = mod + 2;
public
{
	pure nothrow
	{
		///lcm
		T lcm(T)(auto ref T a, auto ref T b)
		{
			return a / gcd(a, b) * b;
		}
		///make_pair
		pair!(X, Y) make_pair(X, Y)(in X x_, in Y y_)
		{
			return tuple!(X, "fi", Y, "se")(x_, y_);
		}
		///BigInt greatest common divizor
		BigInt gcd(BigInt a, BigInt b)
		{
			while (b)
			{
				a %= b;
				swap(a, b);
			}
			return a;
		}
		///square
		@property X sqr(X)(in X a_)
		{
			return a_ * a_;
		}
		///cube
		@property X cub(X)(in X a_)
		{
			return a_ * a_ * a_;
		}
		///integer size
		int sz(T)(T a) if (hasLength!T)
		{
			return cast(int) a.length;
		}
		///posicion lower bound
		size_t lowb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (!(a[m] < g))
					r = m;
				else
					l = m;
			}
			return (!(a[l] < g)) ? l : r;
		}
		///posicion upper bound
		size_t upb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (g < a[m])
					r = m;
				else
					l = m;
			}
			return (g < a[l]) ? l : r;
		}
		///posicion binary search
		size_t binf(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			auto pos = lowb(a, g);
			return (g == a[pos]) ? pos : a.length;
		}
		///binary search
		bool binary_search(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			return binf(a, g) != a.length;
		}
	}
	///write an array
	void putarr(X)(in X a, in char ch = ' ') if (isInputRange!X)
	{
		writefln("%(%s" ~ ch ~ "%)", a);
	}
	///write a matrix
	void putarr(X)(in X a)
			if (isInputRange!X && isInputRange!(ElementType!X) && !isSomeString!(ElementType!X))
	{
		writefln("%(%(%s %)\n%)", a);
	}
	///get an array
	bool getarr(X)(X a, in size_t n)
	{
		bool b = 1;
		foreach (ref i; a[0 .. n])
			b = input(&i);
		return b;
	}
	///read without format
	bool input(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		return s == ptrs.length;
	}
	///readln without format
	bool read(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		readln;
		return s == ptrs.length;
	}
	///opening file
	nothrow auto inf(in char* name)
	{
		return freopen(name, "r", core.stdc.stdio.stdin);
	}
	///closing file
	nothrow auto ouf(in char* name)
	{
		return freopen(name, "w", core.stdc.stdio.stdout);
	}
	///parsing array from line
	@property auto arread(T)()
	{
		return readln.splitter.map!(to!(T)).array;
	}
	///outbuffer
	void enter(T...)(T args)
	{
		writeln(args);
		stdout.flush;
	}
}
//foreach_reverse isAlpha isNumber isWhite isLower isUpper toLower toUpper mixin
//cumulativeFold return static heapify join filter foreach
//------------------------------------------program beginning--------------------------

void main()
{
	version (home)
	{
		// freopen("input.txt", "r", core.stdc.stdio.stdin);
		//freopen("output.txt", "w", core.stdc.stdio.stdout);
		/*StopWatch sw;
		sw.start;
		scope (exit)
		{
			sw.stop;
			stderr.writefln("\nTime: %d ms", sw.peek.msecs);
		}*/
	}
	// int n;
	// loop: while (read(n))
	// {

	// }
	auto gen = Random(unpredictableSeed);
	/*foreach (i; 0 .. 4)
	{
		writeln(uniform(1, 6, gen));
	}*/
	int n, st, x;
	read(n, st, x);
	writeln("? ", st);
	Tuple!(int, int, int)[] d;
	stdout.flush;
	int val, nx;
	read(val, nx);
	d ~= tuple(val, st, nx);

	foreach (_; 0 .. min(n - 1, 999))
	{
		int id = uniform(1, n + 1, gen);
		writeln("? ", id);
		stdout.flush;
		read(val, nx);
		d ~= tuple(val, st, nx);
	}
	sort(d);
	auto pos = lowb(d, tuple(x, 0, 0)) - 1;
	if (pos < 0)
	{
		writeln("! -1");
		stdout.flush;
		return;
	}
	auto h = d[pos];
	foreach (i; 0 .. min(n - 1, 999))
	{
		if (h[0] >= x)
			break;
		writeln("? ", h[2]);
		stdout.flush;
		h[1] = h[2];
		read(h[0], h[2]);
	}
	writeln("! ", h[0]);
	stdout.flush;
}

module main;
__gshared:
import core.bitop, std.algorithm, std.bigint, std.bitmanip, std.complex,
	std.container, std.conv, std.datetime, std.functional, std.math, std.meta;
import std.numeric : Fft, fft, gcd, inverseFft;
import std.parallelism, std.random, std.range, std.regex, std.stdio, std.string,
	std.traits, std.typecons, std.uni, std.variant;

alias pair(X, Y) = Tuple!(X, "fi", Y, "se");
alias mp = make_pair;
alias pii = pair!(int, int);
alias pll = pair!(long, long);
alias gcd = std.numeric.gcd;
alias lint = long;
alias rbt = RedBlackTree;
///modulo
enum mod = 10 ^^ 9 + 7, mod2 = mod + 2;
public
{
	pure nothrow
	{
		///lcm
		T lcm(T)(auto ref T a, auto ref T b)
		{
			return a / gcd(a, b) * b;
		}
		///make_pair
		pair!(X, Y) make_pair(X, Y)(in X x_, in Y y_)
		{
			return tuple!(X, "fi", Y, "se")(x_, y_);
		}
		///BigInt greatest common divizor
		BigInt gcd(BigInt a, BigInt b)
		{
			while (b)
			{
				a %= b;
				swap(a, b);
			}
			return a;
		}
		///square
		@property X sqr(X)(in X a_)
		{
			return a_ * a_;
		}
		///cube
		@property X cub(X)(in X a_)
		{
			return a_ * a_ * a_;
		}
		///integer size
		int sz(T)(T a) if (hasLength!T)
		{
			return cast(int) a.length;
		}
		///posicion lower bound
		size_t lowb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (!(a[m] < g))
					r = m;
				else
					l = m;
			}
			return (!(a[l] < g)) ? l : r;
		}
		///posicion upper bound
		size_t upb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (g < a[m])
					r = m;
				else
					l = m;
			}
			return (g < a[l]) ? l : r;
		}
		///posicion binary search
		size_t binf(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			auto pos = lowb(a, g);
			return (g == a[pos]) ? pos : a.length;
		}
		///binary search
		bool binary_search(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			return binf(a, g) != a.length;
		}
	}
	///write an array
	void putarr(X)(in X a, in char ch = ' ') if (isInputRange!X)
	{
		writefln("%(%s" ~ ch ~ "%)", a);
	}
	///write a matrix
	void putarr(X)(in X a)
			if (isInputRange!X && isInputRange!(ElementType!X) && !isSomeString!(ElementType!X))
	{
		writefln("%(%(%s %)\n%)", a);
	}
	///get an array
	bool getarr(X)(X a, in size_t n)
	{
		bool b = 1;
		foreach (ref i; a[0 .. n])
			b = input(&i);
		return b;
	}
	///read without format
	bool input(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		return s == ptrs.length;
	}
	///readln without format
	bool read(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		readln;
		return s == ptrs.length;
	}
	///opening file
	nothrow auto inf(in char* name)
	{
		return freopen(name, "r", core.stdc.stdio.stdin);
	}
	///closing file
	nothrow auto ouf(in char* name)
	{
		return freopen(name, "w", core.stdc.stdio.stdout);
	}
	///parsing array from line
	@property auto arread(T)()
	{
		return readln.splitter.map!(to!(T)).array;
	}
	///outbuffer
	void enter(T...)(T args)
	{
		writeln(args);
		stdout.flush;
	}
}
//foreach_reverse isAlpha isNumber isWhite isLower isUpper toLower toUpper mixin
//cumulativeFold return static heapify join filter foreach
//------------------------------------------program beginning--------------------------

void main()
{
	version (home)
	{
		// freopen("input.txt", "r", core.stdc.stdio.stdin);
		//freopen("output.txt", "w", core.stdc.stdio.stdout);
		/*StopWatch sw;
		sw.start;
		scope (exit)
		{
			sw.stop;
			stderr.writefln("\nTime: %d ms", sw.peek.msecs);
		}*/
	}
	// int n;
	// loop: while (read(n))
	// {

	// }
	auto gen = Random(unpredictableSeed);
	/*foreach (i; 0 .. 4)
	{
		writeln(uniform(1, 6, gen));
	}*/
	int n, st, x;
	read(n, st, x);
	writeln("? ", st);
	Tuple!(int, int, int)[] d;
	stdout.flush;
	int val, nx;
	read(val, nx);
	d ~= tuple(val, st, nx);

	foreach (_; 0 .. min(n - 1, 999))
	{
		int id = uniform(1, n + 1, gen);
		writeln("? ", id);
		stdout.flush;
		read(val, nx);
		d ~= tuple(val, st, nx);
	}
	sort(d);
	auto pos = lowb(d, tuple(x, 0, 0)) - 1;
	if (pos < 0)
	{
		writeln("! ", d[0][0]);
		stdout.flush;
		return;
	}
	auto h = d[pos];
	foreach (i; 0 .. min(n - 1, 999))
	{
		if (h[0] >= x)
			break;
		if (h[2] == -1)
		{
			writeln("! ", -1);
			stdout.flush;
			return;
		}
		writeln("? ", h[2]);
		stdout.flush;
		h[1] = h[2];
		read(h[0], h[2]);
	}
	writeln("! ", h[0]);
	stdout.flush;
}

module main;
__gshared:
import core.bitop, std.algorithm, std.bigint, std.bitmanip, std.complex,
	std.container, std.conv, std.datetime, std.functional, std.math, std.meta;
import std.numeric : Fft, fft, gcd, inverseFft;
import std.parallelism, std.random, std.range, std.regex, std.stdio, std.string,
	std.traits, std.typecons, std.uni, std.variant;

alias pair(X, Y) = Tuple!(X, "fi", Y, "se");
alias mp = make_pair;
alias pii = pair!(int, int);
alias pll = pair!(long, long);
alias gcd = std.numeric.gcd;
alias lint = long;
alias rbt = RedBlackTree;
///modulo
enum mod = 10 ^^ 9 + 7, mod2 = mod + 2;
public
{
	pure nothrow
	{
		///lcm
		T lcm(T)(auto ref T a, auto ref T b)
		{
			return a / gcd(a, b) * b;
		}
		///make_pair
		pair!(X, Y) make_pair(X, Y)(in X x_, in Y y_)
		{
			return tuple!(X, "fi", Y, "se")(x_, y_);
		}
		///BigInt greatest common divizor
		BigInt gcd(BigInt a, BigInt b)
		{
			while (b)
			{
				a %= b;
				swap(a, b);
			}
			return a;
		}
		///square
		@property X sqr(X)(in X a_)
		{
			return a_ * a_;
		}
		///cube
		@property X cub(X)(in X a_)
		{
			return a_ * a_ * a_;
		}
		///integer size
		int sz(T)(T a) if (hasLength!T)
		{
			return cast(int) a.length;
		}
		///posicion lower bound
		size_t lowb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (!(a[m] < g))
					r = m;
				else
					l = m;
			}
			return (!(a[l] < g)) ? l : r;
		}
		///posicion upper bound
		size_t upb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (g < a[m])
					r = m;
				else
					l = m;
			}
			return (g < a[l]) ? l : r;
		}
		///posicion binary search
		size_t binf(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			auto pos = lowb(a, g);
			return (g == a[pos]) ? pos : a.length;
		}
		///binary search
		bool binary_search(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			return binf(a, g) != a.length;
		}
	}
	///write an array
	void putarr(X)(in X a, in char ch = ' ') if (isInputRange!X)
	{
		writefln("%(%s" ~ ch ~ "%)", a);
	}
	///write a matrix
	void putarr(X)(in X a)
			if (isInputRange!X && isInputRange!(ElementType!X) && !isSomeString!(ElementType!X))
	{
		writefln("%(%(%s %)\n%)", a);
	}
	///get an array
	bool getarr(X)(X a, in size_t n)
	{
		bool b = 1;
		foreach (ref i; a[0 .. n])
			b = input(&i);
		return b;
	}
	///read without format
	bool input(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		return s == ptrs.length;
	}
	///readln without format
	bool read(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		readln;
		return s == ptrs.length;
	}
	///opening file
	nothrow auto inf(in char* name)
	{
		return freopen(name, "r", core.stdc.stdio.stdin);
	}
	///closing file
	nothrow auto ouf(in char* name)
	{
		return freopen(name, "w", core.stdc.stdio.stdout);
	}
	///parsing array from line
	@property auto arread(T)()
	{
		return readln.splitter.map!(to!(T)).array;
	}
	///outbuffer
	void enter(T...)(T args)
	{
		writeln(args);
		stdout.flush;
	}
}
//foreach_reverse isAlpha isNumber isWhite isLower isUpper toLower toUpper mixin
//cumulativeFold return static heapify join filter foreach
//------------------------------------------program beginning--------------------------

void main()
{
	version (home)
	{
		// freopen("input.txt", "r", core.stdc.stdio.stdin);
		//freopen("output.txt", "w", core.stdc.stdio.stdout);
		/*StopWatch sw;
		sw.start;
		scope (exit)
		{
			sw.stop;
			stderr.writefln("\nTime: %d ms", sw.peek.msecs);
		}*/
	}
	// int n;
	// loop: while (read(n))
	// {

	// }
	int n, st, x;
	read(n, st, x);
	writeln("? ", st);
	Tuple!(int, int, int)[] d;
	stdout.flush;
	int val, nx;
	read(val, nx);
	d ~= tuple(val, st, nx);
	auto gen = Random(unpredictableSeed);
	foreach (_; 0 .. 999)
	{
		int id = uniform(1, n, gen);
		writeln("? ", id);
		stdout.flush;
		read(val, nx);
		d ~= tuple(val, st, nx);
	}
	sort(d);
	auto pos = lowb(d, tuple(x, 0, 0)) - 1;
	if (pos < 0)
	{
		writeln("! -1");
		stdout.flush;
		return;
	}
	auto h = d[pos];
	foreach (i; 0 .. 1000 - 1)
	{
		if (h[0] >= x)
			break;
		writeln("? ", h[2]);
		stdout.flush;
		h[1] = h[2];
		read(h[0], h[2]);
	}
	writeln(h[1]);
}

module main;
__gshared:
import core.bitop, std.algorithm, std.bigint, std.bitmanip, std.complex,
	std.container, std.conv, std.datetime, std.functional, std.math, std.meta;
import std.numeric : Fft, fft, gcd, inverseFft;
import std.parallelism, std.random, std.range, std.regex, std.stdio, std.string,
	std.traits, std.typecons, std.uni, std.variant;

alias pair(X, Y) = Tuple!(X, "fi", Y, "se");
alias mp = make_pair;
alias pii = pair!(int, int);
alias pll = pair!(long, long);
alias gcd = std.numeric.gcd;
alias lint = long;
alias rbt = RedBlackTree;
///modulo
enum mod = 10 ^^ 9 + 7, mod2 = mod + 2;
public
{
	pure nothrow
	{
		///lcm
		T lcm(T)(auto ref T a, auto ref T b)
		{
			return a / gcd(a, b) * b;
		}
		///make_pair
		pair!(X, Y) make_pair(X, Y)(in X x_, in Y y_)
		{
			return tuple!(X, "fi", Y, "se")(x_, y_);
		}
		///BigInt greatest common divizor
		BigInt gcd(BigInt a, BigInt b)
		{
			while (b)
			{
				a %= b;
				swap(a, b);
			}
			return a;
		}
		///square
		@property X sqr(X)(in X a_)
		{
			return a_ * a_;
		}
		///cube
		@property X cub(X)(in X a_)
		{
			return a_ * a_ * a_;
		}
		///integer size
		int sz(T)(T a) if (hasLength!T)
		{
			return cast(int) a.length;
		}
		///posicion lower bound
		size_t lowb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (!(a[m] < g))
					r = m;
				else
					l = m;
			}
			return (!(a[l] < g)) ? l : r;
		}
		///posicion upper bound
		size_t upb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (g < a[m])
					r = m;
				else
					l = m;
			}
			return (g < a[l]) ? l : r;
		}
		///posicion binary search
		size_t binf(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			auto pos = lowb(a, g);
			return (g == a[pos]) ? pos : a.length;
		}
		///binary search
		bool binary_search(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			return binf(a, g) != a.length;
		}
	}
	///write an array
	void putarr(X)(in X a, in char ch = ' ') if (isInputRange!X)
	{
		writefln("%(%s" ~ ch ~ "%)", a);
	}
	///write a matrix
	void putarr(X)(in X a)
			if (isInputRange!X && isInputRange!(ElementType!X) && !isSomeString!(ElementType!X))
	{
		writefln("%(%(%s %)\n%)", a);
	}
	///get an array
	bool getarr(X)(X a, in size_t n)
	{
		bool b = 1;
		foreach (ref i; a[0 .. n])
			b = input(&i);
		return b;
	}
	///read without format
	bool input(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		return s == ptrs.length;
	}
	///readln without format
	bool read(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		readln;
		return s == ptrs.length;
	}
	///opening file
	nothrow auto inf(in char* name)
	{
		return freopen(name, "r", core.stdc.stdio.stdin);
	}
	///closing file
	nothrow auto ouf(in char* name)
	{
		return freopen(name, "w", core.stdc.stdio.stdout);
	}
	///parsing array from line
	@property auto arread(T)()
	{
		return readln.splitter.map!(to!(T)).array;
	}
	///outbuffer
	void enter(T...)(T args)
	{
		writeln(args);
		stdout.flush;
	}
}
//foreach_reverse isAlpha isNumber isWhite isLower isUpper toLower toUpper mixin
//cumulativeFold return static heapify join filter foreach
//------------------------------------------program beginning--------------------------

void main()
{
	version (home)
	{
		// freopen("input.txt", "r", core.stdc.stdio.stdin);
		//freopen("output.txt", "w", core.stdc.stdio.stdout);
		/*StopWatch sw;
		sw.start;
		scope (exit)
		{
			sw.stop;
			stderr.writefln("\nTime: %d ms", sw.peek.msecs);
		}*/
	}
	// int n;
	// loop: while (read(n))
	// {

	// }
	auto gen = Random(unpredictableSeed);
	/*foreach (i; 0 .. 4)
	{
		writeln(uniform(1, 6, gen));
	}*/
	int n, st, x;
	read(n, st, x);
	writeln("? ", st);
	Tuple!(int, int, int)[] d;
	stdout.flush;
	int val, nx;
	read(val, nx);
	d ~= tuple(val, st, nx);

	foreach (_; 0 .. min(n - 1, 999))
	{
		int id = uniform(1, n + 1, gen);
		writeln("? ", id);
		stdout.flush;
		read(val, nx);
		if (val == -1)
			assert(0);
		d ~= tuple(val, st, nx);
	}
	auto f = sort(d);
	auto pos = cast(int)(f.lowerBound(tuple(x, 0, 0)).length) - 1;
	if (pos < 0)
	{
		writeln("! ", d[0][0]);
		stdout.flush;
		return;
	}
	auto h = d[pos];
	foreach (i; 0 .. min(n - 1, 999))
	{
		if (h[0] >= x)
			break;
		if (h[2] == -1)
		{
			writeln("! ", -1);
			stdout.flush;
			return;
		}
		writeln("? ", h[2]);
		stdout.flush;
		h[1] = h[2];
		read(h[0], h[2]);
		if (h[0] == -1)
			assert(0);
	}
	writeln("! ", h[0]);
	stdout.flush;
}

module main;
__gshared:
import core.bitop, std.algorithm, std.bigint, std.bitmanip, std.complex,
	std.container, std.conv, std.datetime, std.functional, std.math, std.meta;
import std.numeric : Fft, fft, gcd, inverseFft;
import std.parallelism, std.random, std.range, std.regex, std.stdio, std.string,
	std.traits, std.typecons, std.uni, std.variant;

alias pair(X, Y) = Tuple!(X, "fi", Y, "se");
alias mp = make_pair;
alias pii = pair!(int, int);
alias pll = pair!(long, long);
alias gcd = std.numeric.gcd;
alias lint = long;
alias rbt = RedBlackTree;
///modulo
enum mod = 10 ^^ 9 + 7, mod2 = mod + 2;
public
{
	pure nothrow
	{
		///lcm
		T lcm(T)(auto ref T a, auto ref T b)
		{
			return a / gcd(a, b) * b;
		}
		///make_pair
		pair!(X, Y) make_pair(X, Y)(in X x_, in Y y_)
		{
			return tuple!(X, "fi", Y, "se")(x_, y_);
		}
		///BigInt greatest common divizor
		BigInt gcd(BigInt a, BigInt b)
		{
			while (b)
			{
				a %= b;
				swap(a, b);
			}
			return a;
		}
		///square
		@property X sqr(X)(in X a_)
		{
			return a_ * a_;
		}
		///cube
		@property X cub(X)(in X a_)
		{
			return a_ * a_ * a_;
		}
		///integer size
		int sz(T)(T a) if (hasLength!T)
		{
			return cast(int) a.length;
		}
		///posicion lower bound
		size_t lowb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (!(a[m] < g))
					r = m;
				else
					l = m;
			}
			return (!(a[l] < g)) ? l : r;
		}
		///posicion upper bound
		size_t upb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (g < a[m])
					r = m;
				else
					l = m;
			}
			return (g < a[l]) ? l : r;
		}
		///posicion binary search
		size_t binf(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			auto pos = lowb(a, g);
			return (g == a[pos]) ? pos : a.length;
		}
		///binary search
		bool binary_search(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			return binf(a, g) != a.length;
		}
	}
	///write an array
	void putarr(X)(in X a, in char ch = ' ') if (isInputRange!X)
	{
		writefln("%(%s" ~ ch ~ "%)", a);
	}
	///write a matrix
	void putarr(X)(in X a)
			if (isInputRange!X && isInputRange!(ElementType!X) && !isSomeString!(ElementType!X))
	{
		writefln("%(%(%s %)\n%)", a);
	}
	///get an array
	bool getarr(X)(X a, in size_t n)
	{
		bool b = 1;
		foreach (ref i; a[0 .. n])
			b = input(&i);
		return b;
	}
	///read without format
	bool input(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		return s == ptrs.length;
	}
	///readln without format
	bool read(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		readln;
		return s == ptrs.length;
	}
	///opening file
	nothrow auto inf(in char* name)
	{
		return freopen(name, "r", core.stdc.stdio.stdin);
	}
	///closing file
	nothrow auto ouf(in char* name)
	{
		return freopen(name, "w", core.stdc.stdio.stdout);
	}
	///parsing array from line
	@property auto arread(T)()
	{
		return readln.splitter.map!(to!(T)).array;
	}
	///outbuffer
	void enter(T...)(T args)
	{
		writeln(args);
		stdout.flush;
	}
}
//foreach_reverse isAlpha isNumber isWhite isLower isUpper toLower toUpper mixin
//cumulativeFold return static heapify join filter foreach
//------------------------------------------program beginning--------------------------

void main()
{
	version (home)
	{
		// freopen("input.txt", "r", core.stdc.stdio.stdin);
		//freopen("output.txt", "w", core.stdc.stdio.stdout);
		/*StopWatch sw;
		sw.start;
		scope (exit)
		{
			sw.stop;
			stderr.writefln("\nTime: %d ms", sw.peek.msecs);
		}*/
	}
	// int n;
	// loop: while (read(n))
	// {

	// }
	auto gen = Random(unpredictableSeed);
	/*foreach (i; 0 .. 4)
	{
		writeln(uniform(1, 6, gen));
	}*/
	int n, st, x;
	read(n, st, x);
	writeln("? ", st);
	Tuple!(int, int, int)[] d;
	stdout.flush;
	int val, nx;
	read(val, nx);
	d ~= tuple(val, st, nx);

	foreach (_; 0 .. min(n - 1, 999))
	{
		int id = uniform(1, n + 1, gen);
		writeln("? ", id);
		stdout.flush;
		read(val, nx);
		d ~= tuple(val, st, nx);
	}
	sort(d);
	auto pos = lowb(d, tuple(x, 0, 0)) - 1;
	if (pos < 0)
	{
		writeln("! ", d[0][0]);
		stdout.flush;
		return;
	}
	auto h = d[pos];
	foreach (i; 0 .. min(n - 1, 999))
	{
		if (h[0] >= x)
			break;
		if (h[2] == -1)
		{
			writeln("! ", -1);
			stdout.flush;
			return;
		}
		writeln("? ", h[2]);
		stdout.flush;
		h[1] = h[2];
		read(h[0], h[2]);
		if (h[0] == -1)
			assert(0);
	}
	writeln("! ", h[0]);
	stdout.flush;
}

module main;
__gshared:
import core.bitop, std.algorithm, std.bigint, std.bitmanip, std.complex,
	std.container, std.conv, std.datetime, std.functional, std.math, std.meta;
import std.numeric : Fft, fft, gcd, inverseFft;
import std.parallelism, std.random, std.range, std.regex, std.stdio, std.string,
	std.traits, std.typecons, std.uni, std.variant;

alias pair(X, Y) = Tuple!(X, "fi", Y, "se");
alias mp = make_pair;
alias pii = pair!(int, int);
alias pll = pair!(long, long);
alias gcd = std.numeric.gcd;
alias lint = long;
alias rbt = RedBlackTree;
///modulo
enum mod = 10 ^^ 9 + 7, mod2 = mod + 2;
public
{
	pure nothrow
	{
		///lcm
		T lcm(T)(auto ref T a, auto ref T b)
		{
			return a / gcd(a, b) * b;
		}
		///make_pair
		pair!(X, Y) make_pair(X, Y)(in X x_, in Y y_)
		{
			return tuple!(X, "fi", Y, "se")(x_, y_);
		}
		///BigInt greatest common divizor
		BigInt gcd(BigInt a, BigInt b)
		{
			while (b)
			{
				a %= b;
				swap(a, b);
			}
			return a;
		}
		///square
		@property X sqr(X)(in X a_)
		{
			return a_ * a_;
		}
		///cube
		@property X cub(X)(in X a_)
		{
			return a_ * a_ * a_;
		}
		///integer size
		int sz(T)(T a) if (hasLength!T)
		{
			return cast(int) a.length;
		}
		///posicion lower bound
		size_t lowb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (!(a[m] < g))
					r = m;
				else
					l = m;
			}
			return (!(a[l] < g)) ? l : r;
		}
		///posicion upper bound
		size_t upb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (g < a[m])
					r = m;
				else
					l = m;
			}
			return (g < a[l]) ? l : r;
		}
		///posicion binary search
		size_t binf(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			auto pos = lowb(a, g);
			return (g == a[pos]) ? pos : a.length;
		}
		///binary search
		bool binary_search(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			return binf(a, g) != a.length;
		}
	}
	///write an array
	void putarr(X)(in X a, in char ch = ' ') if (isInputRange!X)
	{
		writefln("%(%s" ~ ch ~ "%)", a);
	}
	///write a matrix
	void putarr(X)(in X a)
			if (isInputRange!X && isInputRange!(ElementType!X) && !isSomeString!(ElementType!X))
	{
		writefln("%(%(%s %)\n%)", a);
	}
	///get an array
	bool getarr(X)(X a, in size_t n)
	{
		bool b = 1;
		foreach (ref i; a[0 .. n])
			b = input(&i);
		return b;
	}
	///read without format
	bool input(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		return s == ptrs.length;
	}
	///readln without format
	bool read(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		readln;
		return s == ptrs.length;
	}
	///opening file
	nothrow auto inf(in char* name)
	{
		return freopen(name, "r", core.stdc.stdio.stdin);
	}
	///closing file
	nothrow auto ouf(in char* name)
	{
		return freopen(name, "w", core.stdc.stdio.stdout);
	}
	///parsing array from line
	@property auto arread(T)()
	{
		return readln.splitter.map!(to!(T)).array;
	}
	///outbuffer
	void enter(T...)(T args)
	{
		writeln(args);
		stdout.flush;
	}
}
//foreach_reverse isAlpha isNumber isWhite isLower isUpper toLower toUpper mixin
//cumulativeFold return static heapify join filter foreach
//------------------------------------------program beginning--------------------------

void main()
{
	version (home)
	{
		// freopen("input.txt", "r", core.stdc.stdio.stdin);
		//freopen("output.txt", "w", core.stdc.stdio.stdout);
		/*StopWatch sw;
		sw.start;
		scope (exit)
		{
			sw.stop;
			stderr.writefln("\nTime: %d ms", sw.peek.msecs);
		}*/
	}
	// int n;
	// loop: while (read(n))
	// {

	// }
	auto gen = Random(unpredictableSeed);
	/*foreach (i; 0 .. 4)
	{
		writeln(uniform(1, 6, gen));
	}*/
	int n, st, x;
	read(n, st, x);
	writeln("? ", st);
	Tuple!(int, int, int)[] d;
	stdout.flush;
	int val, nx;
	read(val, nx);
	d ~= tuple(val, st, nx);

	foreach (_; 0 .. min(n - 1, 999))
	{
		int id = uniform(1, n + 1, gen);
		writeln("? ", id);
		stdout.flush;
		read(val, nx);
		if (val == -1)
			assert(0);
		d ~= tuple(val, st, nx);
	}
	sort(d);
	auto pos = lowb(d, tuple(x, 0, 0)) - 1;
	if (pos < 0)
	{
		writeln("! ", d[0][0]);
		stdout.flush;
		return;
	}
	auto h = d[pos];
	foreach (i; 0 .. min(n - 1, 999))
	{
		if (h[0] >= x)
			break;
		if (h[2] == -1)
		{
			writeln("! ", -1);
			stdout.flush;
			return;
		}
		writeln("? ", h[2]);
		stdout.flush;
		h[1] = h[2];
		read(h[0], h[2]);
		if (h[0] == -1)
			assert(0);
	}
	writeln("! ", h[0]);
	stdout.flush;
}

module main;
__gshared:
import core.bitop, std.algorithm, std.bigint, std.bitmanip, std.complex,
	std.container, std.conv, std.datetime, std.functional, std.math, std.meta;
import std.numeric : Fft, fft, gcd, inverseFft;
import std.parallelism, std.random, std.range, std.regex, std.stdio, std.string,
	std.traits, std.typecons, std.uni, std.variant;

alias pair(X, Y) = Tuple!(X, "fi", Y, "se");
alias mp = make_pair;
alias pii = pair!(int, int);
alias pll = pair!(long, long);
alias gcd = std.numeric.gcd;
alias lint = long;
alias rbt = RedBlackTree;
///modulo
enum mod = 10 ^^ 9 + 7, mod2 = mod + 2;
public
{
	pure nothrow
	{
		///lcm
		T lcm(T)(auto ref T a, auto ref T b)
		{
			return a / gcd(a, b) * b;
		}
		///make_pair
		pair!(X, Y) make_pair(X, Y)(in X x_, in Y y_)
		{
			return tuple!(X, "fi", Y, "se")(x_, y_);
		}
		///BigInt greatest common divizor
		BigInt gcd(BigInt a, BigInt b)
		{
			while (b)
			{
				a %= b;
				swap(a, b);
			}
			return a;
		}
		///square
		@property X sqr(X)(in X a_)
		{
			return a_ * a_;
		}
		///cube
		@property X cub(X)(in X a_)
		{
			return a_ * a_ * a_;
		}
		///integer size
		int sz(T)(T a) if (hasLength!T)
		{
			return cast(int) a.length;
		}
		///posicion lower bound
		size_t lowb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (!(a[m] < g))
					r = m;
				else
					l = m;
			}
			return (!(a[l] < g)) ? l : r;
		}
		///posicion upper bound
		size_t upb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (g < a[m])
					r = m;
				else
					l = m;
			}
			return (g < a[l]) ? l : r;
		}
		///posicion binary search
		size_t binf(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			auto pos = lowb(a, g);
			return (g == a[pos]) ? pos : a.length;
		}
		///binary search
		bool binary_search(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			return binf(a, g) != a.length;
		}
	}
	///write an array
	void putarr(X)(in X a, in char ch = ' ') if (isInputRange!X)
	{
		writefln("%(%s" ~ ch ~ "%)", a);
	}
	///write a matrix
	void putarr(X)(in X a)
			if (isInputRange!X && isInputRange!(ElementType!X) && !isSomeString!(ElementType!X))
	{
		writefln("%(%(%s %)\n%)", a);
	}
	///get an array
	bool getarr(X)(X a, in size_t n)
	{
		bool b = 1;
		foreach (ref i; a[0 .. n])
			b = input(&i);
		return b;
	}
	///read without format
	bool input(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		return s == ptrs.length;
	}
	///readln without format
	bool read(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		readln;
		return s == ptrs.length;
	}
	///opening file
	nothrow auto inf(in char* name)
	{
		return freopen(name, "r", core.stdc.stdio.stdin);
	}
	///closing file
	nothrow auto ouf(in char* name)
	{
		return freopen(name, "w", core.stdc.stdio.stdout);
	}
	///parsing array from line
	@property auto arread(T)()
	{
		return readln.splitter.map!(to!(T)).array;
	}
	///outbuffer
	void enter(T...)(T args)
	{
		writeln(args);
		stdout.flush;
	}
}
//foreach_reverse isAlpha isNumber isWhite isLower isUpper toLower toUpper mixin
//cumulativeFold return static heapify join filter foreach
//------------------------------------------program beginning--------------------------

void main()
{
	version (home)
	{
		// freopen("input.txt", "r", core.stdc.stdio.stdin);
		//freopen("output.txt", "w", core.stdc.stdio.stdout);
		/*StopWatch sw;
		sw.start;
		scope (exit)
		{
			sw.stop;
			stderr.writefln("\nTime: %d ms", sw.peek.msecs);
		}*/
	}
	// int n;
	// loop: while (read(n))
	// {

	// }
	auto gen = Random(unpredictableSeed);
	/*foreach (i; 0 .. 4)
	{
		writeln(uniform(1, 6, gen));
	}*/
	int n, st, x;
	read(n, st, x);
	writeln("? ", st);
	Tuple!(int, int, int)[] d;
	stdout.flush;
	int val, nx;
	read(val, nx);
	d ~= tuple(val, st, nx);

	foreach (_; 0 .. min(n - 1, 999))
	{
		int id = uniform(1, n + 1, gen);
		writeln("? ", id);
		stdout.flush;
		read(val, nx);
		d ~= tuple(val, st, nx);
	}
	sort(d);
	auto pos = lowb(d, tuple(x, 0, 0)) - 1;
	if (pos < 0)
	{
		writeln("! ", d[0][0]);
		stdout.flush;
		return;
	}
	auto h = d[pos];
	foreach (i; 0 .. min(n - 1, 999))
	{
		if (h[0] >= x)
			break;
		writeln("? ", h[2]);
		stdout.flush;
		h[1] = h[2];
		read(h[0], h[2]);
	}
	writeln("! ", h[0]);
	stdout.flush;
}

module main;
__gshared:
import core.bitop, std.algorithm, std.bigint, std.bitmanip, std.complex,
	std.container, std.conv, std.datetime, std.functional, std.math, std.meta;
import std.numeric : Fft, fft, gcd, inverseFft;
import std.parallelism, std.random, std.range, std.regex, std.stdio, std.string,
	std.traits, std.typecons, std.uni, std.variant;

alias pair(X, Y) = Tuple!(X, "fi", Y, "se");
alias mp = make_pair;
alias pii = pair!(int, int);
alias pll = pair!(long, long);
alias gcd = std.numeric.gcd;
alias lint = long;
alias rbt = RedBlackTree;
///modulo
enum mod = 10 ^^ 9 + 7, mod2 = mod + 2;
public
{
	pure nothrow
	{
		///lcm
		T lcm(T)(auto ref T a, auto ref T b)
		{
			return a / gcd(a, b) * b;
		}
		///make_pair
		pair!(X, Y) make_pair(X, Y)(in X x_, in Y y_)
		{
			return tuple!(X, "fi", Y, "se")(x_, y_);
		}
		///BigInt greatest common divizor
		BigInt gcd(BigInt a, BigInt b)
		{
			while (b)
			{
				a %= b;
				swap(a, b);
			}
			return a;
		}
		///square
		@property X sqr(X)(in X a_)
		{
			return a_ * a_;
		}
		///cube
		@property X cub(X)(in X a_)
		{
			return a_ * a_ * a_;
		}
		///integer size
		int sz(T)(T a) if (hasLength!T)
		{
			return cast(int) a.length;
		}
		///posicion lower bound
		size_t lowb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (!(a[m] < g))
					r = m;
				else
					l = m;
			}
			return (!(a[l] < g)) ? l : r;
		}
		///posicion upper bound
		size_t upb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (g < a[m])
					r = m;
				else
					l = m;
			}
			return (g < a[l]) ? l : r;
		}
		///posicion binary search
		size_t binf(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			auto pos = lowb(a, g);
			return (g == a[pos]) ? pos : a.length;
		}
		///binary search
		bool binary_search(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			return binf(a, g) != a.length;
		}
	}
	///write an array
	void putarr(X)(in X a, in char ch = ' ') if (isInputRange!X)
	{
		writefln("%(%s" ~ ch ~ "%)", a);
	}
	///write a matrix
	void putarr(X)(in X a)
			if (isInputRange!X && isInputRange!(ElementType!X) && !isSomeString!(ElementType!X))
	{
		writefln("%(%(%s %)\n%)", a);
	}
	///get an array
	bool getarr(X)(X a, in size_t n)
	{
		bool b = 1;
		foreach (ref i; a[0 .. n])
			b = input(&i);
		return b;
	}
	///read without format
	bool input(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		return s == ptrs.length;
	}
	///readln without format
	bool read(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		readln;
		return s == ptrs.length;
	}
	///opening file
	nothrow auto inf(in char* name)
	{
		return freopen(name, "r", core.stdc.stdio.stdin);
	}
	///closing file
	nothrow auto ouf(in char* name)
	{
		return freopen(name, "w", core.stdc.stdio.stdout);
	}
	///parsing array from line
	@property auto arread(T)()
	{
		return readln.splitter.map!(to!(T)).array;
	}
	///outbuffer
	void enter(T...)(T args)
	{
		writeln(args);
		stdout.flush;
	}
}
//foreach_reverse isAlpha isNumber isWhite isLower isUpper toLower toUpper mixin
//cumulativeFold return static heapify join filter foreach
//------------------------------------------program beginning--------------------------

void main()
{
	version (home)
	{
		// freopen("input.txt", "r", core.stdc.stdio.stdin);
		//freopen("output.txt", "w", core.stdc.stdio.stdout);
		/*StopWatch sw;
		sw.start;
		scope (exit)
		{
			sw.stop;
			stderr.writefln("\nTime: %d ms", sw.peek.msecs);
		}*/
	}
	// int n;
	// loop: while (read(n))
	// {

	// }
	auto gen = Random(unpredictableSeed);
	/*foreach (i; 0 .. 4)
	{
		writeln(uniform(1, 6, gen));
	}*/
	int n, st, x;
	read(n, st, x);
	writeln("? ", st);
	Tuple!(int, int, int)[] d;
	stdout.flush;
	int val, nx;
	read(val, nx);
	d ~= tuple(val, st, nx);

	foreach (_; 0 .. min(n - 1, 999))
	{
		int id = uniform(1, n + 1);
		writeln("? ", id);
		stdout.flush;
		read(val, nx);
		if (val == -1)
			assert(0);
		d ~= tuple(val, st, nx);
	}
	sort(d);
	auto pos = lowb(d, tuple(x, 0, 0)) - 1;
	if (pos < 0)
	{
		writeln("! ", d[0][0]);
		stdout.flush;
		return;
	}
	auto h = d[pos];
	foreach (i; 0 .. min(n - 1, 999))
	{
		if (h[0] >= x)
			break;
		if (h[2] == -1)
		{
			writeln("! ", -1);
			stdout.flush;
			return;
		}
		writeln("? ", h[2]);
		stdout.flush;
		h[1] = h[2];
		read(h[0], h[2]);
		if (h[0] == -1)
			assert(0);
	}
	writeln("! ", h[0]);
	stdout.flush;
}

module main;
__gshared:
import core.bitop, std.algorithm, std.bigint, std.bitmanip, std.complex,
	std.container, std.conv, std.datetime, std.functional, std.math, std.meta;
import std.numeric : Fft, fft, gcd, inverseFft;
import std.parallelism, std.random, std.range, std.regex, std.stdio, std.string,
	std.traits, std.typecons, std.uni, std.variant;

alias pair(X, Y) = Tuple!(X, "fi", Y, "se");
alias mp = make_pair;
alias pii = pair!(int, int);
alias pll = pair!(long, long);
alias gcd = std.numeric.gcd;
alias lint = long;
alias rbt = RedBlackTree;
///modulo
enum mod = 10 ^^ 9 + 7, mod2 = mod + 2;
public
{
	pure nothrow
	{
		///lcm
		T lcm(T)(auto ref T a, auto ref T b)
		{
			return a / gcd(a, b) * b;
		}
		///make_pair
		pair!(X, Y) make_pair(X, Y)(in X x_, in Y y_)
		{
			return tuple!(X, "fi", Y, "se")(x_, y_);
		}
		///BigInt greatest common divizor
		BigInt gcd(BigInt a, BigInt b)
		{
			while (b)
			{
				a %= b;
				swap(a, b);
			}
			return a;
		}
		///square
		@property X sqr(X)(in X a_)
		{
			return a_ * a_;
		}
		///cube
		@property X cub(X)(in X a_)
		{
			return a_ * a_ * a_;
		}
		///integer size
		int sz(T)(T a) if (hasLength!T)
		{
			return cast(int) a.length;
		}
		///posicion lower bound
		size_t lowb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (!(a[m] < g))
					r = m;
				else
					l = m;
			}
			return (!(a[l] < g)) ? l : r;
		}
		///posicion upper bound
		size_t upb(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			size_t l = 0, r = a.length;
			while (r - l > 1)
			{
				auto m = (l + r) >> 1;
				if (g < a[m])
					r = m;
				else
					l = m;
			}
			return (g < a[l]) ? l : r;
		}
		///posicion binary search
		size_t binf(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			auto pos = lowb(a, g);
			return (g == a[pos]) ? pos : a.length;
		}
		///binary search
		bool binary_search(T, X)(T a, auto ref X g)
				if (isRandomAccessRange!T && hasLength!T && is(typeof(g < a[0]) == bool))
		{
			return binf(a, g) != a.length;
		}
	}
	///write an array
	void putarr(X)(in X a, in char ch = ' ') if (isInputRange!X)
	{
		writefln("%(%s" ~ ch ~ "%)", a);
	}
	///write a matrix
	void putarr(X)(in X a)
			if (isInputRange!X && isInputRange!(ElementType!X) && !isSomeString!(ElementType!X))
	{
		writefln("%(%(%s %)\n%)", a);
	}
	///get an array
	bool getarr(X)(X a, in size_t n)
	{
		bool b = 1;
		foreach (ref i; a[0 .. n])
			b = input(&i);
		return b;
	}
	///read without format
	bool input(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		return s == ptrs.length;
	}
	///readln without format
	bool read(T...)(ref T ptrs) if (ptrs.length > 0)
	{
		size_t s = 0;
		foreach (ref e; ptrs)
		{
			if (isSomeChar!(Unqual!(typeof(e))))
				s += readf(" %c", &e);
			else
				s += readf(" %s", &e);
		}
		readln;
		return s == ptrs.length;
	}
	///opening file
	nothrow auto inf(in char* name)
	{
		return freopen(name, "r", core.stdc.stdio.stdin);
	}
	///closing file
	nothrow auto ouf(in char* name)
	{
		return freopen(name, "w", core.stdc.stdio.stdout);
	}
	///parsing array from line
	@property auto arread(T)()
	{
		return readln.splitter.map!(to!(T)).array;
	}
	///outbuffer
	void enter(T...)(T args)
	{
		writeln(args);
		stdout.flush;
	}
}
//foreach_reverse isAlpha isNumber isWhite isLower isUpper toLower toUpper mixin
//cumulativeFold return static heapify join filter foreach
//------------------------------------------program beginning--------------------------

void main()
{
	version (home)
	{
		// freopen("input.txt", "r", core.stdc.stdio.stdin);
		//freopen("output.txt", "w", core.stdc.stdio.stdout);
		/*StopWatch sw;
		sw.start;
		scope (exit)
		{
			sw.stop;
			stderr.writefln("\nTime: %d ms", sw.peek.msecs);
		}*/
	}
	// int n;
	// loop: while (read(n))
	// {

	// }
	auto gen = Random(unpredictableSeed);
	/*foreach (i; 0 .. 4)
	{
		writeln(uniform(1, 6, gen));
	}*/
	int n, st, x;
	read(n, st, x);
	writeln("? ", st);
	Tuple!(int, int, int)[] d;
	stdout.flush;
	int val, nx;
	read(val, nx);
	d ~= tuple(val, st, nx);

	foreach (_; 0 .. min(n - 1, 999))
	{
		int id = uniform(1, n + 1, gen);
		writeln("? ", id);
		stdout.flush;
		read(val, nx);
		d ~= tuple(val, st, nx);
	}
	sort(d);
	auto pos = lowb(d, tuple(x, 0, 0)) - 1;
	if (pos < 0)
	{
		writeln("! -1");
		stdout.flush;
		return;
	}
	auto h = d[pos];
	foreach (i; 0 .. min(n - 1, 999))
	{
		if (h[0] >= x)
			break;
		writeln("? ", h[2]);
		stdout.flush;
		h[1] = h[2];
		read(h[0], h[2]);
	}
	writeln("! ", h[1]);
	stdout.flush;
}

/+ dub.sdl:
    name "B"
    dependency "dcomp" version=">=0.6.0"
+/

import std.stdio, std.algorithm, std.range, std.conv;
// import dcomp.foundation, dcomp.scanner;

int main() {
    auto sc = new Scanner(stdin);
    int n, s, x;
    sc.read(n, s, x); s--;
    int[] v = new int[n];
    int[] nx = new int[n];
    void query(int p) {
        writeln("? ", p+1);
        stdout.flush;
        sc.read(v[p], nx[p]);
        if (nx[p] != -1) nx[p]--;
    }
    void ans(int x) {
        writeln("! ", x);
        stdout.flush;
    }
    import std.random;
    auto gen = Random(unpredictableSeed);
    query(s);
    if (x <= v[s]) {
        ans(v[s]);
        return 0;
    }
    int ma = v[s], mp = s;
    foreach (ph; 0..2) {
        int p = uniform(0, n);
        query(p);
        if (ma < v[p] && v[p] < x) {
            ma = v[p];
            mp = p;
        }
    }
    while (mp != -1) {
        query(mp);
        if (x <= v[mp]) {
            ans(v[mp]);
            return 0;
        }
        mp = nx[mp];
    }
    ans(-1);
    return 0;
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/foundation.d */
// module dcomp.foundation;

static if (__VERSION__ <= 2070) {
    template fold(fun...) if (fun.length >= 1) {
        auto fold(R, S...)(R r, S seed) {
            import std.algorithm : reduce;
            static if (S.length < 2) {
                return reduce!fun(seed, r);
            } else {
                import std.typecons : tuple;
                return reduce!fun(tuple(seed), r);
            }
        }
    }

}
version (X86) static if (__VERSION__ < 2071) {
    import core.bitop : bsf, bsr, popcnt;
    int bsf(ulong v) {
        foreach (i; 0..64) {
            if (v & (1UL << i)) return i;
        }
        return -1;
    }
    int bsr(ulong v) {
        foreach_reverse (i; 0..64) {
            if (v & (1UL << i)) return i;
        }
        return -1;
    }
    int popcnt(ulong v) {
        int c = 0;
        foreach (i; 0..64) {
            if (v & (1UL << i)) c++;
        }
        return c;
    }
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/scanner.d */
// module dcomp.scanner;

class Scanner {
    import std.stdio : File;
    import std.conv : to;
    import std.range : front, popFront, array, ElementType;
    import std.array : split;
    import std.traits : isSomeChar, isStaticArray, isArray;
    import std.algorithm : map;
    File f;
    this(File f) {
        this.f = f;
    }
    char[512] lineBuf;
    char[] line;
    private bool succ() {
        import std.range.primitives : empty, front, popFront;
        import std.ascii : isWhite;
        while (true) {
            while (!line.empty && line.front.isWhite) {
                line.popFront;
            }
            if (!line.empty) break;
            if (f.eof) return false;
            line = lineBuf[];
            f.readln(line);
        }
        return true;
    }

    private bool readSingle(T)(ref T x) {
        import std.algorithm : findSplitBefore;
        import std.string : strip;
        import std.conv : parse;
        if (!succ()) return false;
        static if (isArray!T) {
            alias E = ElementType!T;
            static if (isSomeChar!E) {

                auto r = line.findSplitBefore(" ");
                x = r[0].strip.dup;
                line = r[1];
            } else {
                auto buf = line.split.map!(to!E).array;
                static if (isStaticArray!T) {

                    assert(buf.length == T.length);
                }
                x = buf;
                line.length = 0;
            }
        } else {
            x = line.parse!T;
        }
        return true;
    }
    int read(T, Args...)(ref T x, auto ref Args args) {
        if (!readSingle(x)) return 0;
        static if (args.length == 0) {
            return 1;
        } else {
            return 1 + read(args);
        }
    }
}

/+ dub.sdl:
    name "B"
    dependency "dcomp" version=">=0.6.0"
+/

import std.stdio, std.algorithm, std.range, std.conv;
// import dcomp.foundation, dcomp.scanner;

int main() {
    auto sc = new Scanner(stdin);
    int n, s, x;
    sc.read(n, s, x); s--;
    int[] v = new int[n];
    int[] nx = new int[n];
    void query(int p) {
        writeln("? ", p+1);
        stdout.flush;
        sc.read(v[p], nx[p]);
    }
    void ans(int x) {
        writeln("! ", x);
        stdout.flush;
    }
    import std.random;
    auto gen = Random(unpredictableSeed);
    query(s);
    if (x <= v[s]) {
        ans(v[s]);
        return 0;
    }
    int ma = v[s], mp = s;
    foreach (ph; 0..999) {
        int p = uniform(0, n);
        query(p);
        if (ma < v[p] && v[p] < x) {
            ma = v[p];
            mp = p;
        }
    }

    while (mp == -1 || v[mp] < x) {
        query(mp);
        mp = nx[mp];
    }
    if (mp == -1) ans(-1);
    else ans(v[mp]);
    return 0;
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/foundation.d */
// module dcomp.foundation;

static if (__VERSION__ <= 2070) {
    template fold(fun...) if (fun.length >= 1) {
        auto fold(R, S...)(R r, S seed) {
            import std.algorithm : reduce;
            static if (S.length < 2) {
                return reduce!fun(seed, r);
            } else {
                import std.typecons : tuple;
                return reduce!fun(tuple(seed), r);
            }
        }
    }

}
version (X86) static if (__VERSION__ < 2071) {
    import core.bitop : bsf, bsr, popcnt;
    int bsf(ulong v) {
        foreach (i; 0..64) {
            if (v & (1UL << i)) return i;
        }
        return -1;
    }
    int bsr(ulong v) {
        foreach_reverse (i; 0..64) {
            if (v & (1UL << i)) return i;
        }
        return -1;
    }
    int popcnt(ulong v) {
        int c = 0;
        foreach (i; 0..64) {
            if (v & (1UL << i)) c++;
        }
        return c;
    }
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/scanner.d */
// module dcomp.scanner;

class Scanner {
    import std.stdio : File;
    import std.conv : to;
    import std.range : front, popFront, array, ElementType;
    import std.array : split;
    import std.traits : isSomeChar, isStaticArray, isArray;
    import std.algorithm : map;
    File f;
    this(File f) {
        this.f = f;
    }
    char[512] lineBuf;
    char[] line;
    private bool succ() {
        import std.range.primitives : empty, front, popFront;
        import std.ascii : isWhite;
        while (true) {
            while (!line.empty && line.front.isWhite) {
                line.popFront;
            }
            if (!line.empty) break;
            if (f.eof) return false;
            line = lineBuf[];
            f.readln(line);
        }
        return true;
    }

    private bool readSingle(T)(ref T x) {
        import std.algorithm : findSplitBefore;
        import std.string : strip;
        import std.conv : parse;
        if (!succ()) return false;
        static if (isArray!T) {
            alias E = ElementType!T;
            static if (isSomeChar!E) {

                auto r = line.findSplitBefore(" ");
                x = r[0].strip.dup;
                line = r[1];
            } else {
                auto buf = line.split.map!(to!E).array;
                static if (isStaticArray!T) {

                    assert(buf.length == T.length);
                }
                x = buf;
                line.length = 0;
            }
        } else {
            x = line.parse!T;
        }
        return true;
    }
    int read(T, Args...)(ref T x, auto ref Args args) {
        if (!readSingle(x)) return 0;
        static if (args.length == 0) {
            return 1;
        } else {
            return 1 + read(args);
        }
    }
}

/+ dub.sdl:
    name "B"
    dependency "dcomp" version=">=0.6.0"
+/

import std.stdio, std.algorithm, std.range, std.conv;
// import dcomp.foundation, dcomp.scanner;

int main() {
    auto sc = new Scanner(stdin);
    int n, s, x;
    sc.read(n, s, x); s--;
    int[] v = new int[n];
    int[] nx = new int[n];
    void query(int p) {
        writeln("? ", p+1);
        stdout.flush;
        sc.read(v[p], nx[p]);
    }
    void ans(int x) {
        writeln("! ", x);
    }
    import std.random;
    auto gen = Random(unpredictableSeed);
    query(s);
    if (x <= v[s]) {
        ans(v[s]);
        return 0;
    }
    int ma = v[s], mp = s;
    foreach (ph; 0..999) {
        int p = uniform(0, n);
        query(p);
        if (ma < v[p] && v[p] < x) {
            ma = v[p];
            mp = p;
        }
    }

    while (mp == -1 || v[mp] < x) {
        query(mp);
        mp = nx[mp];
    }
    if (mp == -1) writeln(-1);
    else writeln(v[mp]);
    return 0;
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/foundation.d */
// module dcomp.foundation;

static if (__VERSION__ <= 2070) {
    template fold(fun...) if (fun.length >= 1) {
        auto fold(R, S...)(R r, S seed) {
            import std.algorithm : reduce;
            static if (S.length < 2) {
                return reduce!fun(seed, r);
            } else {
                import std.typecons : tuple;
                return reduce!fun(tuple(seed), r);
            }
        }
    }

}
version (X86) static if (__VERSION__ < 2071) {
    import core.bitop : bsf, bsr, popcnt;
    int bsf(ulong v) {
        foreach (i; 0..64) {
            if (v & (1UL << i)) return i;
        }
        return -1;
    }
    int bsr(ulong v) {
        foreach_reverse (i; 0..64) {
            if (v & (1UL << i)) return i;
        }
        return -1;
    }
    int popcnt(ulong v) {
        int c = 0;
        foreach (i; 0..64) {
            if (v & (1UL << i)) c++;
        }
        return c;
    }
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/scanner.d */
// module dcomp.scanner;

class Scanner {
    import std.stdio : File;
    import std.conv : to;
    import std.range : front, popFront, array, ElementType;
    import std.array : split;
    import std.traits : isSomeChar, isStaticArray, isArray;
    import std.algorithm : map;
    File f;
    this(File f) {
        this.f = f;
    }
    char[512] lineBuf;
    char[] line;
    private bool succ() {
        import std.range.primitives : empty, front, popFront;
        import std.ascii : isWhite;
        while (true) {
            while (!line.empty && line.front.isWhite) {
                line.popFront;
            }
            if (!line.empty) break;
            if (f.eof) return false;
            line = lineBuf[];
            f.readln(line);
        }
        return true;
    }

    private bool readSingle(T)(ref T x) {
        import std.algorithm : findSplitBefore;
        import std.string : strip;
        import std.conv : parse;
        if (!succ()) return false;
        static if (isArray!T) {
            alias E = ElementType!T;
            static if (isSomeChar!E) {

                auto r = line.findSplitBefore(" ");
                x = r[0].strip.dup;
                line = r[1];
            } else {
                auto buf = line.split.map!(to!E).array;
                static if (isStaticArray!T) {

                    assert(buf.length == T.length);
                }
                x = buf;
                line.length = 0;
            }
        } else {
            x = line.parse!T;
        }
        return true;
    }
    int read(T, Args...)(ref T x, auto ref Args args) {
        if (!readSingle(x)) return 0;
        static if (args.length == 0) {
            return 1;
        } else {
            return 1 + read(args);
        }
    }
}

/+ dub.sdl:
    name "B"
    dependency "dcomp" version=">=0.6.0"
+/

import std.stdio, std.algorithm, std.range, std.conv;
// import dcomp.foundation, dcomp.scanner;

int main() {
    auto sc = new Scanner(stdin);
    int n, s, x;
    sc.read(n, s, x); s--;
    int[] v = new int[n];
    int[] nx = new int[n];
    void query(int p) {
        writeln("? ", p+1);
        stdout.flush;
        sc.read(v[p], nx[p]); nx[p]--;
    }
    void ans(int x) {
        writeln("! ", x);
        stdout.flush;
    }
    import std.random;
    auto gen = Random(unpredictableSeed);
    query(s);
    if (x <= v[s]) {
        ans(v[s]);
        return 0;
    }
    int ma = v[s], mp = s;
    foreach (ph; 0..999) {
        int p = uniform(0, n);
        query(p);
        if (ma < v[p] && v[p] < x) {
            ma = v[p];
            mp = p;
        }
    }

    while (mp != -1) {
        query(mp);
        if (x <= v[mp]) {
            ans(v[mp]);
            return 0;
        }
        mp = nx[mp];
    }
    ans(-1);
    return 0;
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/foundation.d */
// module dcomp.foundation;

static if (__VERSION__ <= 2070) {
    template fold(fun...) if (fun.length >= 1) {
        auto fold(R, S...)(R r, S seed) {
            import std.algorithm : reduce;
            static if (S.length < 2) {
                return reduce!fun(seed, r);
            } else {
                import std.typecons : tuple;
                return reduce!fun(tuple(seed), r);
            }
        }
    }

}
version (X86) static if (__VERSION__ < 2071) {
    import core.bitop : bsf, bsr, popcnt;
    int bsf(ulong v) {
        foreach (i; 0..64) {
            if (v & (1UL << i)) return i;
        }
        return -1;
    }
    int bsr(ulong v) {
        foreach_reverse (i; 0..64) {
            if (v & (1UL << i)) return i;
        }
        return -1;
    }
    int popcnt(ulong v) {
        int c = 0;
        foreach (i; 0..64) {
            if (v & (1UL << i)) c++;
        }
        return c;
    }
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/scanner.d */
// module dcomp.scanner;

class Scanner {
    import std.stdio : File;
    import std.conv : to;
    import std.range : front, popFront, array, ElementType;
    import std.array : split;
    import std.traits : isSomeChar, isStaticArray, isArray;
    import std.algorithm : map;
    File f;
    this(File f) {
        this.f = f;
    }
    char[512] lineBuf;
    char[] line;
    private bool succ() {
        import std.range.primitives : empty, front, popFront;
        import std.ascii : isWhite;
        while (true) {
            while (!line.empty && line.front.isWhite) {
                line.popFront;
            }
            if (!line.empty) break;
            if (f.eof) return false;
            line = lineBuf[];
            f.readln(line);
        }
        return true;
    }

    private bool readSingle(T)(ref T x) {
        import std.algorithm : findSplitBefore;
        import std.string : strip;
        import std.conv : parse;
        if (!succ()) return false;
        static if (isArray!T) {
            alias E = ElementType!T;
            static if (isSomeChar!E) {

                auto r = line.findSplitBefore(" ");
                x = r[0].strip.dup;
                line = r[1];
            } else {
                auto buf = line.split.map!(to!E).array;
                static if (isStaticArray!T) {

                    assert(buf.length == T.length);
                }
                x = buf;
                line.length = 0;
            }
        } else {
            x = line.parse!T;
        }
        return true;
    }
    int read(T, Args...)(ref T x, auto ref Args args) {
        if (!readSingle(x)) return 0;
        static if (args.length == 0) {
            return 1;
        } else {
            return 1 + read(args);
        }
    }
}

/+ dub.sdl:
    name "B"
    dependency "dcomp" version=">=0.6.0"
+/

import std.stdio, std.algorithm, std.range, std.conv;
// import dcomp.foundation, dcomp.scanner;

int main() {
    auto sc = new Scanner(stdin);
    int n, s, x;
    sc.read(n, s, x); s--;
    int[] v = new int[n];
    int[] nx = new int[n];
    void query(int p) {
        writeln("? ", p+1);
        stdout.flush;
        sc.read(v[p], nx[p]); nx[p]--;
    }
    void ans(int x) {
        writeln("! ", x);
        stdout.flush;
    }
    import std.random;
    auto gen = Random(unpredictableSeed);
    query(s);
    if (x <= v[s]) {
        ans(v[s]);
        return 0;
    }
    int ma = v[s], mp = s;
    foreach (ph; 0..999) {
        int p = uniform(0, n);
        query(p);
        if (ma < v[p] && v[p] < x) {
            ma = v[p];
            mp = p;
        }
    }

    while (mp == -1) {
        query(mp);
        if (x <= v[mp]) {
            ans(v[mp]);
            return 0;
        }
        mp = nx[mp];
    }
    ans(-1);
    return 0;
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/foundation.d */
// module dcomp.foundation;

static if (__VERSION__ <= 2070) {
    template fold(fun...) if (fun.length >= 1) {
        auto fold(R, S...)(R r, S seed) {
            import std.algorithm : reduce;
            static if (S.length < 2) {
                return reduce!fun(seed, r);
            } else {
                import std.typecons : tuple;
                return reduce!fun(tuple(seed), r);
            }
        }
    }

}
version (X86) static if (__VERSION__ < 2071) {
    import core.bitop : bsf, bsr, popcnt;
    int bsf(ulong v) {
        foreach (i; 0..64) {
            if (v & (1UL << i)) return i;
        }
        return -1;
    }
    int bsr(ulong v) {
        foreach_reverse (i; 0..64) {
            if (v & (1UL << i)) return i;
        }
        return -1;
    }
    int popcnt(ulong v) {
        int c = 0;
        foreach (i; 0..64) {
            if (v & (1UL << i)) c++;
        }
        return c;
    }
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/scanner.d */
// module dcomp.scanner;

class Scanner {
    import std.stdio : File;
    import std.conv : to;
    import std.range : front, popFront, array, ElementType;
    import std.array : split;
    import std.traits : isSomeChar, isStaticArray, isArray;
    import std.algorithm : map;
    File f;
    this(File f) {
        this.f = f;
    }
    char[512] lineBuf;
    char[] line;
    private bool succ() {
        import std.range.primitives : empty, front, popFront;
        import std.ascii : isWhite;
        while (true) {
            while (!line.empty && line.front.isWhite) {
                line.popFront;
            }
            if (!line.empty) break;
            if (f.eof) return false;
            line = lineBuf[];
            f.readln(line);
        }
        return true;
    }

    private bool readSingle(T)(ref T x) {
        import std.algorithm : findSplitBefore;
        import std.string : strip;
        import std.conv : parse;
        if (!succ()) return false;
        static if (isArray!T) {
            alias E = ElementType!T;
            static if (isSomeChar!E) {

                auto r = line.findSplitBefore(" ");
                x = r[0].strip.dup;
                line = r[1];
            } else {
                auto buf = line.split.map!(to!E).array;
                static if (isStaticArray!T) {

                    assert(buf.length == T.length);
                }
                x = buf;
                line.length = 0;
            }
        } else {
            x = line.parse!T;
        }
        return true;
    }
    int read(T, Args...)(ref T x, auto ref Args args) {
        if (!readSingle(x)) return 0;
        static if (args.length == 0) {
            return 1;
        } else {
            return 1 + read(args);
        }
    }
}

module solution;
import std.algorithm;
import std.array;
import std.random;
import std.range;
import std.stdio;
import std.typecons;

immutable int half = 999;
immutable int NA = -1;

void main ()
{
	rndGen.seed (12526362);
	int n, start, x;
	readf (" %s %s %s", &n, &start, &x);
	alias Node = Tuple !(int, q{value}, int, q{next});
	auto a = new Node [n + 1];
	a[] = Node (NA, NA);
	auto p = n.iota.array;
	randomShuffle (p);
	p[] += 1;
	p = p.take (min (half, n)).array;

	void ask (int c)
	{
		if (a[c].value != NA)
		{
			return;
		}
		writeln ("? ", c);
		stdout.flush ();
		readf (" %s %s", &a[c].value, &a[c].next);
	}

	void answer (int v)
	{
		writeln ("! ", v);
		stdout.flush ();
	}

	ask (start);
	int closest = start;
	foreach (c; p)
	{
		ask (c);
		if (a[c].value < x)
		{
			if (a[closest].value < a[c].value)
			{
				closest = c;
			}
		}
	}

	foreach (i; 0..half)
	{
		ask (closest);
		if (a[closest].next == NA)
		{
			answer (NA);
			return;
		}
		if (a[closest].value >= x)
		{
			answer (a[closest].value);
			return;
		}
		closest = a[closest].next;
	}

	assert (false);
}

import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }

uint xrand() {
  static uint x = 314159265, y = 358979323, z = 846264338, w = 327950288;
  uint t = x ^ x << 11; x = y; y = z; z = w; return w = w ^ w >> 19 ^ t ^ t >> 8;
}

// floor(sqrt(a))
long floorSqrt(long a) {
  import core.bitop : bsr;
  import std.algorithm : min;
  long b = a, x = 0, y = 0;
  for (int e = bsr(a) & ~1; e >= 0; e -= 2) {
    x <<= 1;
    y <<= 1;
    if (b >= (y | 1) << e) {
      b -= (y | 1) << e;
      x |= 1;
      y += 2;
    }
  }
  return x;
}

int N, S, X;
debug {
  int[] V, E;
}

alias List = Tuple!(int, "value", int, "next");
List Ask(int i) {
  List ret;
  debug {
    ret.value = V[i];
    ret.next = E[i];
  } else {
    writeln("? ", i + 1);
    stdout.flush;
    ret.value = readInt();
    ret.next = readInt() - 1;
  }
  return ret;
}

void Answer(int v) {
  writeln("! ", v);
  stdout.flush;
  import core.stdc.stdlib;
  exit(0);
}

void main() {
  N = readInt();
  S = readInt() - 1;
  X = readInt();
  debug {
    V = new int[N];
    E = new int[N];
    foreach (i; 0 .. N) {
      V[i] = readInt();
      E[i] = readInt() - 1;
    }
  }

  auto list = new List[N];
  list[] = List(-58, -58);

  list[S] = Ask(S);
  if (list[S].value >= X) {
    Answer(list[S].value);
  }

  int[] perm = iota(N).array;
  foreach (j; 0 .. N) {
    swap(perm[xrand() % (j + 1)], perm[j]);
  }

  int im = S;
  const m = cast(int)(floorSqrt(N));
  foreach (j; 0 .. m) {
    const i = perm[j];
    list[i] = Ask(i);
    if (list[i].value < X) {
      if (im < list[i].value) {
        im = i;
      }
    }
  }

  for (int i = im; ; ) {
    i = list[i].next;
    if (i < 0) {
      Answer(-1);
    }
    list[i] = Ask(i);
    if (list[i].value >= X) {
      Answer(list[i].value);
    }
  }
}